1. Field of the Invention
This invention relates to plume detection of vehicles, particularly vehicles being launched or just launched.
2. Description of Related Art
Clouds can limit the effectiveness of conventional sensors, which employ wide band spectral filters. Typical early missile launch warning systems using passive electro-optical sensors do not see through clouds and may not detect a missile launch at the instant of rocket engine ignition if the missile launch area is obscured by clouds. The time from rocket engine ignition to passing through a cloud layer can be thirty seconds or more. This time delay can be vital for applying countermeasures early in the missile flight path and also for accurate location of the missile launch site not only for further countermeasures but to assist in determining the trajectory of such missile.
Prior art references on the subject include “Spectral Analysis of Low Altitude Theatre-class Missile Signatures”, Selby et al (U), IRIS Targets, Backgrounds and Discrimination, Monterey, Calif., February 1994, but such references employ wide band spectral filters which have limited ability to see through water vapor or clouds.
There is therefore need and market for a missile launch detector that overcomes the above prior art shortcomings.
There has now been discovered a means for promptly detecting and locating vehicle launches through clouds, fog or haze, well before it passes through, e.g., a cloud layer, a gain of thirty seconds or more in early detection.